Spring. The warmer weather is coming, wonderful.
Unfortunately, fly nuisance is also lurking again during this period. Fly nuisance is not only annoying for livestock farmers and their livestock. It also causes stress at cows and flies transmit diseases. The biggest culprit is the stable fly.
There are numerous products available to combat flies, such as: use of predatory flies, sprays, pour-on, ear flaps, fly catchers, traps, granules, maggot kill, etc.
A relatively new method of fly control is the use of predatory flies mentioned above. In recent years, several customers of HappyFarmer tubes containing these predatory flies were deployed. And with success.
In this blog we inform you about the operation and use of these predatory flies.
Predatory flies, mites or wasps?
Robber flies are used in stables with liquid manure cellars. Parasitic wasps can be used in stables with straw or other dry types of manure. If there is an explosion of flies (eg at an early spring with high temperatures, a late start, etc.) it is advisable to use predatory mites as extra support for the predatory flies or parasitic wasps.
Robber fly natural enemy of the stable fly
Stable flies lay their eggs in manure. Wet straw, hay and feed scraps are also used as breeding grounds. Adult females live for 7-10 days and lay up to 800 eggs during that time. The population of stable flies is therefore increasing rapidly.
The predatory fly is a natural enemy of the stable fly: the larva of the predatory fly feeds on the stable fly larva. This causes the stable fly larvae to die and cannot develop into a stable fly.
Laboratory fly
HappyFarmer supplies cardboard tubes containing pupae of the predatory fly Ophyra aenescens. This fly is bred in laboratories and is guaranteed not to transmit any pathogens and therefore poses no risk to the health of livestock. The adult predatory fly is smaller than the stable fly. It is easily recognized by its black color with metal-shiny body.
The predatory flies are not a nuisance to humans and animals, they are light-shy and stay in the manure cellar.
Use predatory flies
The predatory flies are supplied in cardboard tubes containing pupae. After removing the lid, the tubes are hung up at places where there is fly nuisance. After 2 – 5 days the first adult predatory flies emerge from the pupae. They are immediately ready to reproduce: they lay their eggs on the manure.
To build and maintain an effective population of predatory flies, it is important to use the cardboard tubes several times a year.
The advice is to use the tubes in the starting year as follows:
- Start in March/April.
- Insert the tubes for the first 3 times every 14 days.
- Then every 4 weeks.
- The tubes are used a total of 6 times in the first year.
In subsequent years, installing tubes once every 13 weeks is sufficient.
Tips for optimal operation
To optimally use predatory flies, the following points are required:
- Remove spilled food residues at least once a week. The stable fly is then forced to reproduce in the manure.
- Manure that is too dry slows down the development of the predatory fly, because it lays its eggs on the border between dry and wet. Wet the manure regularly. Not too wet; there should always be a thin layer of crust.
- Do not mix manure.
- Always leave about four inches of manure in the cellar. If all manure is removed, almost the entire population of predatory flies will be destroyed.
Example costs
A tube robber flies for 75m² stable surface at HappyFarmer €24,65.
For a Barn Eleven tubes are required per treatment for an area of 825 m².
The costs are per treatment €271,15.
Six treatments are required for the first year. The total costs in the first year are: €1.626,90.
Four treatments are recommended in the following year (every 13 weeks). The costs then amount to: €1.084,60.